This invention relates to a cushioned floor covering article wherein the mat includes a tufted carpet placed on the top side of a foam rubber sheet and at least one foam rubber protrusion integrated within at least a portion of the bottom side of the foam rubber sheet. Such an article provides effective removal of moisture, dirt, and debris from the footwear of pedestrians through the utilization of a carpet pile component. Furthermore, the utilization of a foam rubber backing also allows for either periodic heavy duty industrial-scale laundering in such standard washing machines or periodic washing and drying in standard in-home machines, both without appreciably damaging the inventive floor covering article, such as a floor mat. Additionally, the presence of integrated foam rubber protrusions within the mat structure provides an effective cushioning effect for pedestrian comfort as well as a means to prevent slippage of the article from its contacted surface. A method of producing such an inventive cushioned floor covering article is also provided.
All U.S. patent cited herein are hereby fully incorporated by reference.
Floor mats have long been utilized to facilitate the cleaning of the bottoms of people""s shoes, particularly in areas of high pedestrian traffic such as doorways. Moisture, dirt, and debris from out of doors easily adhere to such footwear, particularly in inclement weather and particularly in areas of grass or mud or the like. Such unwanted and potentially floor staining or dirtying articles need to be removed from a person""s footwear prior to entry indoors. As will be appreciated, such outdoor mats by their nature must undergo frequent repeated washings and dryings so as to remove the dirt and debris deposited therein during use. These mats are generally rented from service entities which retrieve the soiled mats from the user and provide clean replacement mats on a frequent basis. The soiled mats are thereafter cleaned and dried in an industrial laundering process (such as within rotary washing and drying machines, for example) and then sent to another user in replacement of newly soiled mats. Furthermore, it is generally necessary from a health standpoint to produce floor coverings on which persons may stand for appreciable amounts of time which will provide comfort to such persons to substantially lower the potential for fatigue of such persons by reducing the stress on feet and leg joints through cushioning.
Typical carpeted dust control mats comprise solid and/or foam rubber backing sheets which must be cleated in some manner to prevent slippage of the mat from its designated area. Such cleats are formed during a vulcanization step and have required a time-consuming procedure of placing the green (unvulcanized) rubber sheet on a molded silicone pad and then removing the same after vulcanization. Also, the thicknesses of such dust control rubber backing sheets are generally quite low and thus permit the placement of a pedestrian""s foot relatively close to the covered floor or ground when he steps on such a mat. As a result, and particularly if the covered area is hard, the mat does not appreciably cushion the pedestrian""s foot. With a general shift toward providing protection to pedestrians, particularly outside entryways of stores, where a cushioned, non-slip dust control mat will provide a safe, comfortable floor covering on which a customer may clean his footwear, and workplaces, where a person may be required to be mobile for an appreciable amount of time during the workday and thus a non-slip, cushioned floor covering provides a certain degree of safety to a user, there is a recognized need to provide non-slip floor and/or ground coverings which can potentially reduce the stress of a pedestrian""s leg and foot joints through the benefit of cushioning characteristics. There have been a few advancements within the prior art for providing cushioning within dust control mats, such as U.S. Pat. No. 5,645,914 to Horowitz. Generally, such cushioning benefits are provided in either only all-rubber mats, as in U.S. Pat. No. 3,016,317 to Brunner, or solely provide such cushioning benefits within or on the top side of the mat, as in U.S. Pat. No. 4,262,048 to Mitchell. Also, cleated backings have been produced in the past to provide non-slip characteristics, such as in U.S. Pat. No. 4,741,065 to Parkins. Such mats do not also provide cushioning characteristics with the same non-slip components, however. As such, there still exists a need to reduce cost for producing overall dust control mat products through a process wherein the cushioning characteristic are simultaneously provided by the same non-slip mechanism. To date, the prior art has neither taught nor fairly suggested such a combination of elements in a cushioned carpeted floor covering article.
It is thus an object of this invention to provide a non-slip, cushioned, anti-fatigue carpeted floor covering article which permits cleaning of a pedestrian""s footwear. Furthermore, it is an object of the invention to provide a carpeted floor covering article for which the portion which provides the cushioning characteristics simultaneously provides non-slip benefits. An additional object of this invention is to provide a non-slip, cushioned, antifatigue carpeted floor covering article in which the cushioning aspects are provided by at least one integrated rubber protrusion produced during the necessary vulcanization process. Still a further object of the invention is to provide a non-slip, cushioned carpeted floor covering article which possesses sufficient flexibility to withstand periodical laundering in industrial washing and drying machines. Yet another object of this invention is to provide a floor covering article which can substantially reduce a person""s fatigue after standing on such an article for appreciable periods of time as compared with other standard floor covering articles.
Accordingly, this invention encompasses a cushioned floor covering article comprising
a carrier fabric;
a pile material tufted into the carrier fabric which forms a pile surface on one side of the carrier fabric; and
a vulcanized expanded backing sheet of rubber attached to the other side of the carrier fabric, wherein at least one protrusion integrated within said backing sheet is present on the side of the backing opposite the side to which the carrier fabric is attached. Also, this invention encompasses a method of forming a cushioned floor covering article comprising the steps of
(a) placing a sheet of rubber over a die having at least a first and second side, wherein said rubber optionally comprises a blowing agent to form a closed-cell foam rubber structure upon vulcanization, wherein said die has portions thereof removed to allow for the entry of molten rubber, and wherein said die is comprised of a material which can withstand vulcanization temperatures and pressures;
(b) tufting a pile material into a carrier fabric to form a tufted pile surface extending from one side of the carrier fabric;
(c) laying the carrier fabric with tufted pile onto the rubber sheet of step xe2x80x9caxe2x80x9d;
(d) optionally, placing solid rubber reinforcing strips around at least one of the border edges of the rubber sheet; and
(e) subjecting the composite comprising the rubber sheet, the die, the carrier fabric, the carpet pile, and the optional reinforcing strips to vulcanization temperatures and pressures to (1) attach the rubber sheet to the side of the carrier fabric from which the pile surface does not extend, and (2) to form rubber protrusions through the removed portions of the die.
The inventive dust control mat generally comprises any type of standard carpet pile fibers tufted through any standard type of carrier fabric. Such carpet fibers may be natural or synthetic, including, without limitation, cotton, ramie, wool, polyester, nylon, polypropylene, and the like, as well as blends of such fibers (all as merely examples). The fibers may be coarse or fine in structure as well. Such fiber structures are represented in dust control mats within U.S. Pat. No. 1,008,618, to Skowronski et al., U.S. Pat. No. 4,045,605, to Breens et al., and U.S. Pat. No. 4,353,944, to Tarui, U.S. Pat. Nos. 4,820,566 and 5,055,333, both to Heine et al., as well as within French Patent No. 1,211,755, assigned to Cosyntex (S.A.), and PCT Application 95/30040, assigned to Kleen-Tex Industries, Inc. Of particular interest in this invention, however, are 100% solution dyed nylon fibers. Such pile fibers provide the best pile surface for overprinting with different dyes in order to provide the most aesthetically pleasing colorations and shades on the floor mat pile surface. The carrier fabric may thus be of any construction, such as woven, non-woven, knit, and the like. Preferably, a woven or non-woven substrate is utilized. The carpet pile is tufted through the carrier fabric in a standard tufting process for further placement on and attachment during vulcanization to the top side of the rubber backing sheet.
The carpet fibers may be colored or dyed through any acceptable methods so as to produce aesthetically pleasing designs within the carpet pile portion of the inventive mat. Of particular importance, however, is the utilization of an overprinting procedure of 100% solution dyed nylon fibers. Such nylon is acid-dyeable and available from Cookson Fibers. As noted above, such pile fibers allow for the most pleasing and long-lasting colorations and shades of color to be applied and retained on the pile surface through the utilization of acid dyes. With such fibers, any design or configuration may be produced (as well as logos, pictures, and the like) on the pile surface, again in order to provide a long-lasting aesthetically pleasing floor mat for the consumer. Furthermore, the inventive article itself can be made in any shape, with rectangular or square configurations being preferred.
In actuality, the attachment of the rubber sheet component to the carpet pile fibers may be accomplished either during the actual vulcanization step, as taught in Nagahama, for example, above, or through the use of an adhesive layer, preferably a polyolefin adhesive, between the carpet pile and the rubber sheet, as disclosed in copending U.S. patent application Ser. No. 08/732,866, to Kerr, hereby entirely incorporated by reference, or any other like procedure.
The rubber backing sheet may be comprised of any standard rubber composition, including, but not limited to, acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), ethylene-propylene-diene comonomer rubber (EPDM), carboxylated NBR, carboxylated SBR, chlorinated rubber, silicon-containing rubber, and the like. For cost purposes, the preferred rubbers are NBR, SBR, EPDM and blends thereof.
The rubber composition may be of solid or foam construction or there may be layers of both present on the inventive mat. Preferably, the majority of the rubber composition within the backing sheet is of foam construction (which requires the presence of a blowing agent to form closed-cell structures within the rubber upon vulcanization, such as in U.S. Pat. No. 5,305,565 to Nagahama et al.). The target thickness for such a rubber sheet is from about 5 to about 500 mils, preferably from about 25 to about 400 mils, more preferably from about 40 to about 250 mils, and most preferably from about 75 to about 200 mils.
Floor mats and other like floor covering articles have exhibited general problems arising from frequent washings and harsh environments of use. First, the energy required to wash and dry a typical floor mat is significant due to the overall mass of the mats. This overall mass is made up of the mass of the mat pile, the mass of the carrier fabric into which the mat pile is tufted, and most significantly, the mass of the rubber backing sheet which is integrated to the carrier fabric under heat and pressure. As will be appreciated, a reduction in the overall mass of the floor mat will result in a reduced energy requirement in washing and drying the mat. Moreover, a relative reduction in the mass of the rubber backing sheet (i.e. the heaviest component) will provide the most substantial benefit. Thus, the utilization of a lighter weight rubber composition, such as foam rubber, in at least a portion of the dust control mat of the present invention includes a rubber backing sheet which may possess a specific gravity which is approximately 25-35 percent less then the solid rubber sheets of typical prior floor mats. Accordingly, a foam rubber is preferably, though not required, as the rubber structure of the inventive mat""s rubber backing sheet. This lighter weight thus translates into a reduced possibility of the mat harming either the washing or drying machine in which the mat is cleaned, or the mat being harmed itself during such rigorous procedures. Although the inventive floor mat must withstand the rigors of industrial machine washing, hand washing and any other manner of cleaning may also be utilized. Overall, the inventive floor mat provides an article which will retain its aesthetically pleasing characteristics over a long period of time and which thereby translates into reduced costs for the consumer.
Solid rubber reinforcement strips may also be added around the borders of the mat, either by hand or in an in-line process, such as in Patent Cooperation Treaty Application 96/38298, to Milliken Research Corporation. Such strips must either possess roughly the same shrinkage rate factor as the carpet pile substrate and the foam rubber backing sheet or they must possess roughly the same modulus strength of the solid rubber backing sheet, all in order to ensure the probability of rippling (or curling) of the mat will be minimal. Such strips may be comprised of any type of butadiene rubber, such as acrylonitrile-butadiene (NBR) or styrene-butadiene (SBR), or carboxylated derivatives of such butadienes, merely as examples. Preferably, the strips are comprised of NBR as carboxylated NBR is cost prohibitive. Such strips can be of any general width and as long as the specific side upon which they are attached on the backing sheet. The target thickness for such strips second layer is from about 2 to about 50 mils, preferably from about 4 to about 40 mils, more preferably from about 5 to about 35 mils, and most preferably from about 5 to about 25 mils. Furthermore, if such strips are applied, they should be placed on top of the backing sheet prior to the placement of the carpet pile if the width of such strips, as measured from the border of the sheet, is greater then the width of the area from the border to the carpet pile, in order to permit overlap of the strips and the carpet pile while simultaneously permitting adhesion of the strips to the sheet.
Furthermore, a significant problem exists within this field concerning the deterioration of the carbon-carbon double bonds in the matrix of the rubber backing sheet due to the exposure of the sheets to an oxidizing environment during use and cleaning. Specifically, the exposure of the mats to oxidizing agents during the washing and drying process tends to cleave the carbon-carbon double bonds of the rubber sheet thereby substantially embrittling the rubber which leads to cracking under the stress of use. In addition to the laundering process, the exposure of the mats to oxygen and ozone, either atmospheric or generated, during storage and use leads to cracking over time. The mat of the present invention may thus include an ozone-resistance additive, such as ethylene-propylene-diene monomer rubber (EPDM), as taught within U.S. Pat. No. 5,902,662, to Kerr, which provides enhanced protection to the rubber backing sheet against oxygen in order to substantially prolong the useful life of the mat. Such an additive also appears to provide a reduction in staining ability of such rubber backed mats upon contact with various surfaces, such as concrete, wood, and a handler""s skin, just to name a few, as discussed in U.S. patent application Ser. No. 09/113,842 to Rockwell, Jr.
U.S. Pat. No. 5,305,565, to Nagahama et al., previously entirely incorporated by reference, shows the usual manner of producing floor mats comprising carpet pile fibers, a carpet pile substrate, and a rubber backing sheet. This reference, however, makes no mention as to the production of at least one integrated rubber protrusion from the side of the backing sheet opposite the carpet pile component. The term xe2x80x9cintegrated rubber protrusionxe2x80x9d is intended to encompass any type of protrusion from the rubber backing sheet which is formed from the same backing sheet composition and is not attached in any manner to the resultant backing sheet after vulcanization. Thus, such a protrusion would be produced through the flowing of the rubber composition during vulcanization and allowing molten rubber to form around a die mold in a position in which it remains until it cures and sets. The shape of such a protrusion is virtually limitless, and may be of any size. Furthermore, it is possible to construct sheet wherein the body of the structure comprises a blowing agent (to produce a foam rubber) and a second layer of solid rubber covers the body portion. In such a manner, the protrusions could be formed with a core of foam rubber and a cap of solid rubber (upon vulcanization through a die-mold, for example). As such, preferably the protrusion or protrusions are formed from all foam rubber (which provides better cushioning). The separate protrusions thus provide discrete areas of relaxed stress within the inventive mat which thus provides a cushioning effect to a pedestrian, greater than for an overall flat foam rubber structure.
As noted previously, since the protrusion or protrusions are both located on the bottom side of the backing sheet and extend from the sheet itself, such a protrusion or protrusions provides a non-slip character to the overall mat structure. Since the length of the protrusions cannot be greater than the depth of the backing sheet itself (since it is vulcanized on a solid surface, the resultant protrusions are formed through the embedding of the die-mold within the backing sheet during vulcanization; removed portions of the die provide the holes in which the protrusions are ultimately formed from molten, then cooled rubber), such protrusions, being separate from the body of the mat through some type of shaft (again of any size and shape), form xe2x80x9cfeetxe2x80x9d which can grip the surface on which the mat is placed and create difficulty in moving the mat through a pushing motion parallel to such a surface. Thus, the protrusions also provide a non-slip characteristic to the inventive mat. Again, as noted above, there has been no teaching or fair suggestion of such an advantage (in cost, at least) for an aesthetically pleasing carpeted dust control mat.
With regard to the die, it may be constructed of any material which can withstand vulcanization temperatures (i.e., between about 250xc2x0 F. and about 350xc2x0 F.) and pressures (i.e., between about 15 psi and 50 psi, generally). Thus, any metal may be utilized, certain plastics, such as Teflon(copyright), for example, silicon molds, and the like. Preferably, the die is made of steel, is generally square or rectangular in shape (although any shape may be utilized), and comprises holes throughout to ultimately form the desired protrusions. Preferably, such holes are circular in shape (at the die surface) and cylindrical as well (i.e., circular on both surfaces with the same shape throughout the die from one surface to the other). Furthermore, such a die may also be utilized in an in-line process wherein there is no need to hand place the backing sheet over the die itself. The preferred procedure is outlined more particularly below.
The inventive mat provides a long-lasting non-slip, cushioned carpeted article which provides comfort to users as well as significantly reduced changes of slipping, all in a one-step procedure. All of this translates into reduced cost for the consumer as costs to produce are lower and possible medical and insurance costs may also be reduced with the utilization of such specific mats which also work to remove dirt and moisture from the pedestrians"" footwear.